Declarative Aggregators

[Grauenwolf]

Syntax:

ds.From( table, [filter] ).ToAggregate<TCollection, TObject>( [having filter] )

New Attributes:

• GroupBy (index)
• Aggregate (aggregationType)
• Aggregate (customExpression)

Rules:

1. If the property has both a GroupBy and an Aggregate attribute, throw an XXX exception.
2. If the property has either a GroupBy or an Aggregate attribute, honor it.
3. If the property is the name of a column, use it for grouping.
4. If the property is in the format of [AggregateType][ColumnName], treat it as if it had an Aggregate attribute. Example: MaxCustomerKey would generate Max(CustomerKey) As MaxCustomerKey

[Grauenwolf]

We should be able to use one attribute with three overloads.

The GroupBy overload will accept an integer to indicate the order.

[Grauenwolf]

To activate this, use the .AsAggregate<T> method on the command builder. The T is the object that will store the aggregation.

In the future, consider adding support for a HAVING clause.

[Grauenwolf]

There will also be an .AsAggregate() method for use when the table name was inferred from the class name.